Interesting. I have used free marker. Pretty happy with it in general. But inability to mutate collections is an annoyance.

I will checkout blueprint. A zero dependency library is always a bonus. I don’t see any mention of thread safety in the docs for the engine though.

Hey, Blueprint rendering was already thread-safe. Only the function/filter registrations, IF done during rendering phase, was not thread-safe.

I have just pushed small update to make even these thread-safe now. Entire library is now fully thread-safe.

Updated README as well.

Thanks for pointing this out.